1. Field of the Invention
This invention relates to chalk line devices used for establishing a line between two points during construction work by the employment of a flexible string or line carrying chalk.
2. Brief Description of the Prior Art
A number of devices have heretofore been proposed for use by carpenters and in similar trades for the purpose of establishing an identifiable marked out line between two points. One of the most widely used of these devices is a chalk line device which includes a chalk-containing housing which also contains a reel upon which a flexible string or the like is reeled, and is paid out through a hole in one end of the chalk-containing housing. At its end outside the housing, the string will usually carry some type of ring or clip which will permit that end of the string to be secured in a fixed positon. The housing can then be drawn away from the outer end of the string, after it is fixed in place, to a second location to which it is desired to establish a marked line. As the housing is moved away from the anchored end of the chalk line, the line is paid out from the reel and in moving through the body of chalk dust carried within the housing, picks up a significant amount of chalk which adheres to the line. After the two points between which the line is to be established have been determined, and the housing then placed at one end and the free end of the string at the other, the string can be snapped to cause the chalk to be jarred therefrom and left in a line corresponding to the extension of the string between the two points.
Although the chalk line device, per se, is old in the art, in recent times several improvements on these very useful adjuncts to the carpenter's trade have been developed. Thus, in U.S. Pat. No. 2,589,500 to Linden et al., the housing which contains the chalk dust and the reel upon which the chalk line is stored is made in a shape or configuration which permits it to be used as a plumb bob. This can be accomplished by reeling out the chalk line carrying a loop or ring at its free end outside the housing to a point where the line can be suspended from an overhead location, and the housing permitted to swing pendulum fashion from such point of suspension. The lower end of the housing comes to rest over a point which is directly below, and in vertical alignment with, the anchored free end of the chalk line.
This form of the chalk and reel housing has been retained in a more recent type of chalk line device as shown in Landen U.S. Pat. No. 2,749,618. The Landen patent includes a quick opening and closing pivoted plate which is mounted through an opening at one side of the chalk box to permit the box to be quickly refilled with chalk dust at a time when the supply has become exhausted through use of the device.
In U.S. Pat. No. 3,126,637 to Short, a dual line chalk box is provided which contains a pair of reels disposed on opposite sides of a chamber containing the chalk dust, with the respective chalk lines carried on these reels being paid out through openings formed in opposite ends of the housing. By dividing the chamber in which the two reels are located into two separate chambers, two colors of chalk dust may be utilized so that the two chalk lines snapped at different places or for different purposes may be distinguished by the use of either one of the lines, according to the color of chalk dust carried thereby.
More recent improvements in chalk line devices are depicted in U.S. Pat. No. 3,438,595 to Brown et al. and U.S. Pat. No. 3,888,018 to Hyde et al.